The prodromata consist, as in most psychoses, in change of disposition, insomnia, and impairment of general health.

Schematically we may distinguish in the delusional form of dementia praecox two extreme types which are connected by a great many intermediate types: (1) the incoherent type; (2) the systematized type.

(1) Dementia Praecox With Incoherent Delusions

As this name indicates, the delusions and the numerous hallucinations which usually accompany them follow each other without any connection or governing idea, and are accepted by the patient as they appear, without any attempt on his part to find an explanation or interpretation for them.

The general character of the delusions may be of three varieties:

(a) Depressive Variety: Melancholy delusions associated with more or less marked depression and hallucinations of a painful nature. Often ideas of persecution are added to the melancholy ideas, and occasionally they even predominate. It is not rare to encounter, especially at the beginning of the disease, attacks of very pronounced anxiety, suicidal ideas and attempts, or violent tendencies.

(b) Maniacal Variety: Excitement, irritability, morbid euphoria, ideas of grandeur occasionally associated with ideas of persecution, numerous hallucinations, erotic tendencies, and sometimes a certain degree of confusion.

(c) Mixed Variety: The two preceding varieties are seldom met with in a state of purity. They are almost always combined with each other in one of two different wavs:'

(1) States of depression and those of excitement alternate without any order, and mutually replace each other every instant; in other words, the delusional state is polymorphous.

(2) The disease develops in three stages:

I. Depression with melancholy delusions;

II. Excitement with expansive delusions;

III. Dementia.

Sometimes, as in catatonia, the disease assumes a circular type. There are recurrent attacks, each consisting of a phase of depression and one of excitement and leaving behind each time a more pronounced state of deterioration.

(2) Dementia Praecox With Systematized Delusions

This is the type to which the term paranoid dementia is most applicable. The systematization of the delusions is not equally accurate in all cases. Sometimes it is quite perfect, so that the disease resembles paranoia. In other cases the systematization is, on the contrary, so imperfect that one hesitates to classify the case as dementia praecox with systematized delusions. We have already seen that there exists between the two delusional forms of dementia praecox an infinity of intermediate forms.

Lucidity is preserved except during the transitory acute paroxysms, which are of frequent occurrence.

Hallucinations are frequent and affect all the senses.

Dementia supervenes after a variable period of time, which is in some cases very long. As it progresses the number of delusions becomes more and more limited, the hallucinations diminish in frequency and in intensity, and the reactions become weaker and weaker. Often the system of delusions is reduced to one or two morbid ideas, crystallized, so to speak, and constituting a paranoic residue which remains as the last vestige of the delusional state originally characterizing the affection. Neologisms are frequent in the period of dementia.